1. Field of the Invention
This invention relates to data storage and, more particularly, to techniques for communicating information in storage systems.
2. Description of the Related Art
Many business organizations and governmental entities rely upon applications that access large amounts of data, often exceeding a terabyte or more of data, for mission-critical applications. Often such data is stored on many different storage devices, which may be centrally located or distributed throughout an enterprise. Such storage devices may be heterogeneous in nature, including many different types of devices from many different manufacturers.
To provide for a degree of security against loss of critical data, for example due to a hardware or software failure, critical data may be stored on several volumes, where one volume is configured to mirror another. One of the mirrored volumes may thus provide a backup source of data in case another one of the mirrored volumes fails.
If a failure occurs during system operation, mirrored data volumes may not reflect the same data (i.e., may become inconsistent), for example if data is written to one mirrored volume but not another. In some cases, inconsistent mirrors may need to be resynchronized following a failure in order for applications to continue operating properly. However, preventing applications from using the mirrored volumes until they are completely resynchronized may result in large application downtimes or unacceptable performance degradation.